Correct, D605 is free for all LCN2Kai unit owners if you complain that your NC unit constantly restarts. It has no other improvements than this field fix. Restart of NC is caused by changes in DAB broadcasted synchro messages which may overload the buffer which causes CPU to restart the unit.

And if I disable the DAB in NC unit and no restart then do I need thid D605 update? Thanks!

Found this thread when wonderign why our QQ kept flipping from DAB to FM on a trek down south last week.. looks like I have D302 installed on my Connect unit.

Can I go straight to D554 if I acquire the files or even if D605 is around or is D605 dealer only ?

Already been in for an AC compressor replacement, then back as they'd forgotten to service it prior to sale so got a major service done for free (as well as giving them the chance to reconnect the front camera they forgot about when in for the AC) - does the Nissan warranty cover head unit code updates?